Heater unit construction



Oct. 31, 1944. w, J, RUSSELL 2,361,874

HEATER UNIT CONSTRUCTION Original Filed Sept. 14, 1938 WITNESSES:

INVENTOR WILLIAM J.Ru5sE1.L.

V ATTOR Y Patented Oct; 31, 1944:

nEA'rEn, .UNI rcoNs'rR oTioN William J; Russell, Mansfield, Ohio, assignor to Westinghouse Electric. & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Substituted. for abandonedxapplication Serial No. 229,851, September 14, 1938. This application April 3, 1941, Serial No. 386,630

1 Claim.

bodying my invention, taken alongthe line I-I of F18. 3;

Fig, 2 is enlarged fragmentary view similar to Fig: 1.; and,

Fig. 3 is a top plan. viewof the device shown in Fig. 1.

Referringto the. accompanying drawing, I show aheating unit iflvincluding.aanat-surface plate H having two elongated spiral grooves l2 formed therein, armored heating elements I 3.01 substan tially triangular cross-section, positioned within the respective grooves I2: and rigidly attached thereto, and. afsuitablesupporting structure II for thep ate I land-heating elements: i3.

The, triangular-sectioned or armored heating; elements l3 each comprise a sheath i5; insulatingmaterial l6 anda coiled resistance element I1. The coil. i1 is triangular in cross-section and is. insulatedly supported within the sheath-15% by means of suitable insulating material i6; suchiasmagnesium oxide, pressed into a soli'dihomogeneousrmass substantially as shown in Figs. 1 andi2; The metallic'armor or sheath l5 is also triangular in cross-section and permits cooking vessels or the like. to be freelyplaced on the fiatupper'surfacethereof without anydanger of injuring the heating element. In addition, this metallic sheath permits. the heating element 13 to be rigidly attached to the top surface of the plate H as by brazing or welding the sheath. to the wall of the elongated grooves i2 substantially as shown at it in-Fig; 2.

The fiat-surface plate II is, in this instance,

formed from any well-known materialwhich will permit theheating unit to operate at a red heat; The plate: l'l i'spreferablyformed in a single die= castingoperation, the elongated grooves I! being formed therein to conformto the configuration three-sided associated with the supporting structure of the heating elements 13.

the supporting structure I: to'form an integral unit, as hereinafter described.

unit will be'high, inasmuch as cooking vessels placed thereon are in direct contact with the heating elements over a large area provided by the flat upper sides of the heating elements. Further, a portion of the heat produced within the heating, elements radiates from the lower walls thereof and is reflected upwardly toward the cooking vessel by the fiat-surface plate II. In addition, a portion of the heat produced within the heating elements is directly conducted therefrom to the flat-surface plate l2, permitting a large portion of such conducted heat to be directly radiated to the bottom surface of the cooking vessel. These additional paths for the transfer of heat from the armored elongated heating elements it to the cooking vessel are an important factor in materially increasing theheating efliciency of the heating unit i (i.

The flat-surface plate Il may be operatively through the cooperation of the depending side portion I9 0! the plate H. The supporting structure I4 is preferably formed of a dish-shaped member 2| having an upwardly-extending side wall 22 to cooperate with the dependingportion I9 of the plate ll. rigidly attached heating elements 13 is positioned over the supporting structure it, whereupon the depending side portion is of the plate ,Il engages the upwardly-extending side portion 22 of the structure l3. In addition, a bolt 23 rigidly attached to the central portion; of the plate: H may be rigidly attached to the supporting structure it so as to form anintegral unit therewith. A plurality of terminals 24 extending f-rom' the heating elements may be positioned at the lower portion of the supporting structure It to afford. cooperation with a suitable power supply. In addition, if desired, a heat-insulating or heat-reflecting member 25 may be positioned intermediate the surface plate ii and the lower portion of the supporting'structure H to retard the downward travel of heat and to reflect such downwardly-traveling heat upwardly.

It is to be understood that'the supporting structure M as hereinabove. described is merely ineluded to form a complete heating unit, and that such supporting structure is not to be considered a part of my invention.

Various further modifications may be made in This plate has a depending side portion is which cooperates with It is apparent that the eificiency of the heating The plate Ii, including the sulating said resistance element from said sheath, 1.)

the cross-section of said tubular sheath in the usable heatlng portion thereof comprising three flat side wall portions disposed in triangular formation and three rounded connecting portions joining said side wall portions at the three apices of the triangular formation, the side wall portions of said sheath being substantially parallel to adjacent sides of said coil, said sheath being coiled in a flat spiral with one oi the flat side wall portions disposed in a plane and disposed with the rounded connecting portion opposite the lastmentioned side wall portion down within said groove and in contact with said plate, and means for rigidly attaching said sheath to said plate. WILLIAM J. RUSSELL. 

